Have a 1986 Merc Black Max 175 that will not shut down when key is turned to the off position... it will idle down but not completley shutdown.... any thoughts?
That motor needs to provide a ground to the switchboxes to kill the spark. The ign killer wire should be black/yellow. Check it at the switchboxes and see if it is grounded with the ign key in the off position.
I will look into that Chris.... i dont think my switch is bad at all because when it is in the "off" position every thing else will shut off exept for the engine
There is a circuit inside the switch that kills the engine by completing a path to ground . It doesnt matter that everything else is turned off if the engine is still running. Either your wiring to ground is bad or your switch is bad. I dont have any in depth root cause analysis numbers in front of me but If I said 99 times out of 100 you problem is caused by the switch, I probably wouldn't be far off.
The ignition switch is TWO switches within the one housing. One set of contacts handles the 12V duties, the separate set of contacts grounds that B/Y wire to the solid B wire to kill spark.
Most likely the one set of contacts has failed. Prove it with an Ohm meter than count how many wires are on the switch as there is more than one switch available, the number of wires is important.
